A problem in the area of air care devices is the uncontrolled “distillation” of fragrance components of differing volatilities, resulting in a variable fragrance profile over time, as perceived by the consumer. The use of carriers or solvents in fragrances aids in the uniform distribution or evaporation of these fragrance components and leads to a more homogeneous fragrance profile.
Many materials are used as carriers in air care devices including glycol ethers, isoparaffinic solvents (e.g., Isopar® solvents commercially available from ExxonMobil) and various branched esters. One problem associated with these materials is that many are classified as VOCs (volatile organic compounds). VOC's are increasingly of environmental and regulatory concern. There is one class of VOCs, low vapor pressure VOC's (LVP-VOCs), which are not as harmful to the atmosphere and are generally allowed under even the most stringent environmental regulations. This class of VOC has lower vapor pressure than regular VOCs as defined by standard definitions (e.g., <0.1 mm Hg at 20° C.).
The use of Dowanol DPMA (dipropylene glycol methyl ether acetate) has low vapor pressure VOC in fragrance composition is known from U.S. Pat. No. 8,603,963. However, it presents a very low evaporation rate (1.5, n-butyl acetate=100), it comes from petrochemical source and also presents a non-pleasure odor. In some devices, like reed diffusers, the odor of the solvent could be an issue since this can compete with the fragrance. Concerning the very low evaporation rate of Dowanol, it is also an issue in reed diffusers since the weight loss of the fragrance composition must be between 2.0-3.0 g/day to have a good spread in the environment.
Alkyl-4-hydroxymethyl-1,3-dioxolane molecules are known to be used in many different applications like coatings, paints, cleaning compositions, actives solubilization, because of their good solubilization properties, good physical-chemical properties, low odor and good HSE profile, that can replace products from petrochemical sources. However, those molecules have never been used is fragrance compositions, notably for air devices.
There is still a need for new fragrance compositions that have a reduced content of high vapor pressure VOCs. For example, there is a need for fragrance compositions whose solvents or carriers are mainly low vapor pressure VOCs, notably for use in liquid electrical air fresheners, such as a heated wick delivery systems, piezoelectrical spraying systems, electrospray devices, Venturi devices or wicking devices as reed diffusers. It is desired to provide fragrance compositions suitable for use in air fresheners that avoid the regulatory problems associated with many of the glycol ether compounds commonly found in liquid electrical air fresheners and reed diffusers. It is also desired to provide-fragrance compositions wherein the evaporation rate is regulated to within a predetermined period of time (e.g., 30 days, or 40 days, or 60 days), during which at least substantially all of the fragrance is effectively evaporated into the surrounding environment, preferably in a controlled fashion.
It is thus an object to provide fragrance compositions that contain mainly low pressure VOCs, as solvents or carriers that are economical to produce and have good safety characteristics, including low toxicity and low flammability. Advantageously it is an object to provide such fragrances compositions wherein the low vapor pressure VOCs, used as solvents or carriers are synthesized from renewable sources.
Another and related object of the invention is to provide fragrance compositions that contain essentially low pressure VOCs, as solvents or carriers having a controllable evaporation rate and that are suitable for use in, for example, a wick type air fragrance dispenser (air freshener) like reed diffusers. More specifically, it is an object of the invention to provide a controllable evaporation rate and permit effective utilization of the fragrance composition in a liquid electrical air freshener dispenser and/or in wick devices like reed diffusers.